On 23 October 1999, Beyer won his first world title against WBC super middleweight champion Richie Woodhall. He successfully defended the title against Leif Keiski before losing it to Glenn Catley.

On 5 April 2003, Beyer challenged Canadian WBC super middleweight champion Eric Lucas and was awarded a highly controversial split decision in Germany.[1] It was later proven that Beyer's team cheated by obtaining the judges' scores during the fight.[2] Beyer defended the title against Danny Green and Andre Thysse before being upset by Cristian Sanavia. Beyer defeated Sanavia by knockout in a rematch then went on to retain the title five times by scoring wins over Yoshinori Nishizawa, Danny Green, Omar Sheika, Alberto Colajanni, and a draw against Sakio Bika.

On 14 October 2006, Beyer lost his title via third-round knockout to WBA super middleweight champion Mikkel Kessler in a unification fight.